EP2553412A1 - Thermocouple electromotive force voltage to temperature converter with integrated cold-junction compensation and linearization - Google Patents
Thermocouple electromotive force voltage to temperature converter with integrated cold-junction compensation and linearizationInfo
- Publication number
- EP2553412A1 EP2553412A1 EP11714173A EP11714173A EP2553412A1 EP 2553412 A1 EP2553412 A1 EP 2553412A1 EP 11714173 A EP11714173 A EP 11714173A EP 11714173 A EP11714173 A EP 11714173A EP 2553412 A1 EP2553412 A1 EP 2553412A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- cold junction
- digital
- junction temperature
- integrated circuit
- thermocouple
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
- 238000009529 body temperature measurement Methods 0.000 claims abstract description 10
- 238000004891 communication Methods 0.000 claims abstract description 8
- 230000009977 dual effect Effects 0.000 claims description 3
- 230000008878 coupling Effects 0.000 claims 5
- 238000010168 coupling process Methods 0.000 claims 5
- 238000005859 coupling reaction Methods 0.000 claims 5
- 238000005259 measurement Methods 0.000 abstract description 8
- 238000005516 engineering process Methods 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 230000006870 function Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
- G01K7/10—Arrangements for compensating for auxiliary variables, e.g. length of lead
- G01K7/12—Arrangements with respect to the cold junction, e.g. preventing influence of temperature of surrounding air
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
- G01K7/14—Arrangements for modifying the output characteristic, e.g. linearising
Definitions
- the present disclosure relates to mixed signal integrated circuits, and more particularly, to mixed-signal integrated circuits used with thermocouple sensors and having a programmable analog amplifier, National Institute of Standards and Technology (NIST) based thermocouple linearization tables, an isothermal block temperature sensor for cold- junction compensation, and, optionally, an input multiplexer and/or registers for storing measured temperature values, high and low set points, and/or alarm limits.
- NIST National Institute of Standards and Technology
- thermocouple temperature sensor instrumentation interfaces comprise complex, power consuming, and a costly plurality of analog instrumentation and linearization circuits.
- Cold-junction compensation is generally implemented using a discrete standalone sensor such as a thermistor or RTD.
- a low power integrated circuit solution for commercial and industrial equipment thermal management that comprises a direct instrument interface to and linearization of the voltages from at least one thermocouple, with cold- junction temperature compensation and conversion of those linearized and cold-junction temperature compensated voltages to temperature measurement units, e.g., Centigrade, Fahrenheit, Kelvin, etc., over a wide measurement temperature range with excellent measurement accuracy and resolution.
- temperature measurement units e.g., Centigrade, Fahrenheit, Kelvin, etc.
- a measurement temperature range from about -270 degrees Celsius to about 1300 degrees Celsius and having a temperature measurement resolution of better than 0.5 degrees Celsius.
- a mixed-signal integrated circuit comprises: 1 ) an analog front end having differential inputs adapted for directly connecting to at least one thermocouple, 2) an analog-to-digital (ADC) for converting the thermocouple voltages to digital representations thereof, 3) a linearization circuit capable of performing the multi-order polynomial equations for converting the thermocouple electromotive voltages (the digital representations) to linear temperature measurement units by using coefficients unique to each type of thermocouple from a coefficients table based upon the National Institute of Standards and Technology (NIST), 4) an integrated cold-junction temperature sensor for measuring cold junction temperature, and 5) a communications interface for setting parameters and receiving temperature information.
- ADC analog-to-digital
- an input multiplexer for selecting each of a plurality of thermocouples for measurement thereof, 7) an analog programmable gain amplifier (PGA), and 8) registers for storing measured temperature values, high and low set points, alarm limits, etc.
- the linearization circuit may be part of a digital processor having a memory, e.g., a microcontroller, microprocessor, digital signal processor, application specific integrated circuit (ASIC), programmable logic array (PLA), etc.
- the digital processor may also control the input multiplexer, PGA, store the register values in the memory, and communicate via a serial interface.
- the ADC measures the thermocouple(s) electromotive force (EMF) voltage(s) generated at the thermocouple hot-junction at typically a measurement resolution of about two (2) microvolts per least significant bit (LSb).
- EMF electromotive force
- the cold-junction temperature sensor measures the ambient temperature of the thermocouple cold-junction.
- the digital processor e.g., microcontroller, reads the ADC output data and the integrated temperature sensor data.
- the digital ADC output data and the integrated temperature sensor are summed and then linearized using a polynomial equation of as high as 9 th order depending upon the type of thermocouple being used.
- the coefficients used in the polynomial equation are supplied from a look-up table having appropriate values for each type of thermocouple, wherein these values are standard values provided by the National Institute of Standards and Technology (NIST).
- NIST National Institute of Standards and Technology
- the digital data may be converted to desired temperature measurement units, e.g., Centigrade, Fahrenheit, Kelvin, etc., over a wide measurement temperature range with excellent measurement accuracy and resolution.
- desired temperature measurement units e.g., Centigrade, Fahrenheit, Kelvin, etc.
- the corrected, linearized and converted temperature measurement units may be available through a serial interface, e.g., I 2 C, SPI, etc., and/or may be stored in registers of a memory.
- Figure 1 illustrates a schematic block diagram of an analog front end of a thermocouple interface and linearization integrated circuit device, according to a specific example embodiment
- Figure 2 illustrates a schematic block diagram of a digital processing back end of a thermocouple interface and linearization integrated circuit device, according to a specific example embodiment.
- thermocouple interface and linearization integrated circuit device may comprise an analog multiplexer 106, a programmable gain amplifier (PGA) 104, an analog-to-digital converter (ADC) 102, and a cold junction temperature sensor 112.
- An external to the integrated circuit device is an isothermal block 108 used for connection to the cold junctions of at least one thermocouple 1 10.
- the cold junction temperature sensor 112 is thermally coupled to the isothermal block 108.
- the cold junction temperature from the cold junction temperature sensor 1 12 is used in the temperature correction of the linearized temperature values of the at least one thermocouple 1 10.
- the analog multiplexer 106 enables interfacing to a plurality of thermocouples 110a- 1 1 On (through the isothermal block 108).
- the PGA 104 may be used to increase the analog input sensitivity of the ADC 102.
- the analog multiplexer 106, the PGA 104 and the ADC 102 may be controlled by data acquisition and control logic 226 ( Figure 2).
- the ADC 102 may be, for example but is not limited to, a Delta-Sigma ADC.
- thermocouple interface and linearization integrated circuit device may comprise a linearization processor 218, a table of NIST coefficients 220, a digital summer 222, a cold junction temperature interface 224, data acquisition and control logic 226, memory and/or registers 228, and a communications interface 230, e.g., serial I 2 C, SPI, SMBus, etc.
- the linearization logic 218 solves for an appropriate to the thermocouple type, e.g., J, K, B, E, N, R, S, T, etc., multi-order polynomial equation using the NIST constants stored in the table of NIST coefficients 220.
- the table of NIST coefficients 220 may be stored in a non-volatile memory, e.g., electrically erasable and programmable read only memory (EEPROM).
- a cold-junction temperature adjustment is made in the digital summer 222.
- the purpose of the cold junction temperature adjustment is to normalize the thermocouple hot- junction values to a 0 degree Centigrade reference temperature.
- the cold-junction temperature sensor 112 may be, for example but not limited to, a thermistor, RTD, etc., and its analog output may be converted into digital values with the cold-junction temperature interface 224 before being applied to the digital summer 222.
- the data acquisition and control logic 226 may be used to convert the linearized and normalized digital temperature values from the digital summer 222 into desired temperature measurement units, e.g., Centigrade, Fahrenheit, Kelvin, etc.
- the data acquisition and control logic 226 may also store and/or compare various measured temperature values in the memory/registers 228. High and low limit temperature values may be stored in the memory/registers 228 for alarm and/or control functions.
- the communications interface 230 may be used for reading the temperature values. controlling temperature related activities, e.g., process control; entering set points and alarm limits into the memory/registers 228, etc.
- Integrated circuit packages for the thermocouple interface and linearization integrated circuit device may be, for example but not limited to, Mini Small Outline Package (MSOP), Small Outline Integrated Circuit (SOIC), Dual Flat No- Lead (DFN), etc.
- MSOP Mini Small Outline Package
- SOIC Small Outline Integrated Circuit
- DFN Dual Flat No- Lead
- the DFN package is preferred due to its better cold junction thermal conduction when the integrated circuit package is closely coupled thermally to the isothermal block 108.
- a mixed-signal integrated circuit device such as a microcontroller may include all elements disclosed herein except for the isothermal block 108 and thermocouples 110.
- the isothermal block 108 may be adapted to facilitate connecting to the cold side wires of the at least one thermocouple 110, e.g., screw terminals for ease of connection to the wires of the thermocouple 110. It is the intention of this disclosure to present a simple, low cost and easy to implement, but powerful, integrated circuit device for facilitating integration and use of thermocouples into commercial and industrial temperature monitoring and control systems.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US31985410P | 2010-03-31 | 2010-03-31 | |
US12/851,631 US8485724B2 (en) | 2010-03-31 | 2010-08-06 | Thermocouple electromotive force voltage to temperature converter with integrated cold-junction compensation and linearization |
PCT/US2011/030143 WO2011123377A1 (en) | 2010-03-31 | 2011-03-28 | Thermocouple electromotive force voltage to temperature converter with integrated cold-junction compensation and linearization |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2553412A1 true EP2553412A1 (en) | 2013-02-06 |
Family
ID=44709644
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP11714173A Ceased EP2553412A1 (en) | 2010-03-31 | 2011-03-28 | Thermocouple electromotive force voltage to temperature converter with integrated cold-junction compensation and linearization |
Country Status (6)
Country | Link |
---|---|
US (1) | US8485724B2 (en) |
EP (1) | EP2553412A1 (en) |
KR (1) | KR101742188B1 (en) |
CN (1) | CN102782468B (en) |
TW (1) | TWI516752B (en) |
WO (1) | WO2011123377A1 (en) |
Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008304425A (en) * | 2007-06-11 | 2008-12-18 | Yokogawa Electric Corp | Temperature measurement device |
US8182139B2 (en) * | 2008-05-30 | 2012-05-22 | Apple Inc. | Calibration of temperature sensing circuitry in an electronic device |
US8794830B2 (en) * | 2010-10-13 | 2014-08-05 | Biosense Webster, Inc. | Catheter with digitized temperature measurement in control handle |
US9429478B2 (en) * | 2012-02-10 | 2016-08-30 | Extron Company | Thermocouple with integrity monitoring |
FR2993981B1 (en) * | 2012-07-24 | 2015-04-03 | Commissariat Energie Atomique | SELF-CALIBRATION CALORIMETER BY ELECTRICAL SUBSTITUTION |
US20140050248A1 (en) * | 2012-08-15 | 2014-02-20 | Bae Systems Controls Inc. | I/o connector incorporating a cold junction |
CN103029566B (en) * | 2013-01-10 | 2015-05-06 | 安徽江淮汽车股份有限公司 | Cooling control circuit of motor controller of electric automobile |
US9279731B2 (en) * | 2013-03-12 | 2016-03-08 | Lam Research Corporation | Multichannel thermocouple compensation for three dimensional temperature gradient |
KR101704222B1 (en) * | 2015-06-24 | 2017-02-08 | 엘에스산전 주식회사 | Method for temperature drift compensation of temperature measurement device using thermocouple |
DE102015113842A1 (en) * | 2015-08-20 | 2017-02-23 | Endress + Hauser Wetzer Gmbh + Co. Kg | Temperature measuring device with reference temperature determination |
FR3063343B1 (en) * | 2017-02-28 | 2019-06-07 | Safran Helicopter Engines | THERMOMETRIC MEASUREMENT BY MESHING PROBES, IN PARTICULAR WITHIN TURBOMACHINES |
CN107024297A (en) * | 2017-04-25 | 2017-08-08 | 淮阴师范学院 | A kind of sensor compensator of thermocouple |
CN107449521B (en) * | 2017-07-31 | 2020-01-17 | 深圳市泰和安科技有限公司 | Temperature compensation method, terminal device and computer readable storage medium |
JP6851299B2 (en) * | 2017-10-31 | 2021-03-31 | 三菱電機株式会社 | Temperature measuring device |
JP6973161B2 (en) * | 2018-02-21 | 2021-11-24 | オムロン株式会社 | Temperature measuring device, ambient temperature measuring method, and ambient temperature measuring program |
CN109459155B (en) * | 2018-11-16 | 2024-03-15 | 天水电气传动研究所有限责任公司 | Temperature detection device for high-voltage high-current special power supply |
CN111912539A (en) * | 2020-08-14 | 2020-11-10 | 北京优航机电技术有限公司 | K-type thermocouple nonlinear correction method based on double fitting algorithm |
CN114544021B (en) * | 2022-01-13 | 2024-07-23 | 成都金知丽科技有限公司 | Cold end temperature estimation method of multichannel temperature acquisition system based on heat conduction combined signal reconstruction |
US20240142315A1 (en) * | 2022-11-01 | 2024-05-02 | Foreman Instrumentation & Controls, Inc. | Modified Thermocouple Assembly |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4482261A (en) * | 1982-07-15 | 1984-11-13 | Owens-Corning Fiberglas Corporation | Method for simultaneous reference junction compensation of a plurality of thermocouples |
CN2426143Y (en) * | 2000-04-30 | 2001-04-04 | 西门子数控(南京)有限公司 | Temp. measuring circuit in plastics ejection moulding machine |
US20040008725A1 (en) * | 2002-07-15 | 2004-01-15 | Analog Devices, Inc. | Method and an interface circuit configurable in two communication protocol modes |
JP2004085384A (en) * | 2002-08-27 | 2004-03-18 | Seiko Epson Corp | Temperature sensor circuit, semiconductor integrated circuit, and its regulating method |
US7489022B2 (en) * | 2005-08-02 | 2009-02-10 | Viasat, Inc. | Radio frequency over-molded leadframe package |
-
2010
- 2010-08-06 US US12/851,631 patent/US8485724B2/en active Active
-
2011
- 2011-03-14 TW TW100108580A patent/TWI516752B/en active
- 2011-03-28 KR KR1020127019738A patent/KR101742188B1/en active IP Right Grant
- 2011-03-28 EP EP11714173A patent/EP2553412A1/en not_active Ceased
- 2011-03-28 WO PCT/US2011/030143 patent/WO2011123377A1/en active Application Filing
- 2011-03-28 CN CN201180012162.1A patent/CN102782468B/en active Active
Non-Patent Citations (1)
Title |
---|
BOB DOBKIN ET AL: "MAX6675 Cold-Junction-Compensated K-Thermocouple-to-Digital Converter", 1 January 2002 (2002-01-01), Saint Louis, XP055442259, ISBN: 978-0-12-800001-4, Retrieved from the Internet <URL:http://web.archive.org/web/20090206012300if_/http://pdfserv.maxim-ic.com:80/en/ds/MAX6675.pdf> [retrieved on 20180118] * |
Also Published As
Publication number | Publication date |
---|---|
US8485724B2 (en) | 2013-07-16 |
WO2011123377A1 (en) | 2011-10-06 |
TW201205053A (en) | 2012-02-01 |
KR20130042462A (en) | 2013-04-26 |
KR101742188B1 (en) | 2017-05-31 |
CN102782468B (en) | 2015-03-25 |
TWI516752B (en) | 2016-01-11 |
CN102782468A (en) | 2012-11-14 |
US20110243188A1 (en) | 2011-10-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8485724B2 (en) | Thermocouple electromotive force voltage to temperature converter with integrated cold-junction compensation and linearization | |
Duff et al. | Two ways to measure temperature using thermocouples feature simplicity, accuracy, and flexibility | |
ES2705433T3 (en) | Method for temperature drift compensation of temperature measurement device using thermocouple | |
US5857777A (en) | Smart temperature sensing device | |
JP5414788B2 (en) | Apparatus for linearizing nonlinear sensors | |
US8996327B2 (en) | Enhancing thermocouple temperature measurement accuracy with local RTDs to compensate terminal temperature difference | |
US20170328790A1 (en) | System and Method for Temperature Sensing | |
US20060262829A1 (en) | Infrared temperature sensing device | |
Eke et al. | Design and implementation of a low-cost multi-channel temperature measurement system for photovoltaic modules | |
WO2023272908A1 (en) | High-precision temperature measurement method and system | |
US20120219035A1 (en) | Temperature estimation apparatus and method in thermocouple input module of plc | |
CN111272297A (en) | Electronic body temperature gun | |
CN111189561A (en) | Ultra-high temperature far-end temperature measurement calibration method, measurement calibration circuit and medium | |
Jovanović et al. | NTC thermistor nonlinearity compensation using Wheatstone bridge and novel dual-stage single-flash piecewise-linear ADC | |
Engin et al. | Compensation of thermocouple nonlinearities with embedded system | |
JPS60169729A (en) | Calibrating method of temperature sensitive element and temperature measuring method using temperature sensitive element | |
CN108195477B (en) | Temperature sensor with adjustable precision and testing method | |
US10942069B2 (en) | Temperature measurement apparatus | |
CN111765985A (en) | Circuit and method for realizing high-precision temperature measurement based on 12-bit ADC (analog to digital converter) | |
Huang et al. | The Design of Measurement System Based on Digital Temperature Sensors | |
CN107505843B (en) | Active thermal control optimization method for space optical payload | |
CN112729583A (en) | SPARC microcontroller-based thermocouple type analog input module | |
Жилинский et al. | AUTOMATION OF THE TEMPERATURE MEASURING AND FIXING PROCESS BASED ON THE NI CDAQ-9181 CONTROLLER AND THE NI USB-6008 | |
JPH11281489A (en) | Thermometer and temperature measuring method | |
CN115900978A (en) | Multichannel wireless temperature acquisition device and environment temperature wireless acquisition system |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20121022 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
DAX | Request for extension of the european patent (deleted) | ||
17Q | First examination report despatched |
Effective date: 20160826 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: EXAMINATION IS IN PROGRESS |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R003 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
|
18R | Application refused |
Effective date: 20180624 |